Torque distribution systems in automotive vehicles may control division of torque between two axle shafts by way of a torque transfer coupling.
Generally, when one of the axle shafts starts to slip, such systems typically apply a greater portion of torque the other axle shaft until the appropriate wheel torque is achieved. More specifically, when the wheel associated with the axle shaft is on a slick road condition or loose gravel, the wheel may initially lose traction. The system subsequently applies a greater portion of the available torque, e.g., received from a propeller shaft, to the other axle shaft, thereby improving traction. Additionally, electronic controls may be employed to selectively balance torque application between the two axle shafts and allowing a greater degree of control and/or intervention.
Known twin electronic torque distribution systems generally are bulky and are difficult to package in a vehicle, especially in view of the desire to maintain identical or similar packaging widths of the overall system within a vehicle. In particular, known dual electronically controlled torque distribution systems require added width to accommodate the additional size required to fit the two separate electronic control systems, including the clutch packs and associated activation devices. The increased cross-vehicle width of these electronically controlled torque distribution systems makes provision of such systems as an option on a vehicle difficult, as manufacturers have a strong preference for maintaining commonality to the extent possible across all options associated with a vehicle line. Additionally, the increased cross-vehicle width causes the inboard side shaft joints to be positioned or shifted towards the wheel, leading to packaging conflicts with chassis components and an increase in joint angles of the axle shafts, decreasing efficiency of the system and durability of system components, e.g., constant velocity joints.
Therefore, there is a need for an axle module that includes an integration of two electronically controlled axle shafts into a smaller package in order to allow for a greater number of practical applications of this technology. Additionally, there is a need for reduced weight and lower side shaft joint angles within the torque distribution system to increase durability and provide appropriate traction performance for all wheel drive systems.